1. Field of the Invention
The present invention relates to a semiconductor device and a method for manufacturing the same.
2. Description of the Related Art
With the downsizing of electronic equipment, demand for semiconductor devices applying a QFN (Quad Flat Non-leaded Package) is growing.
A semiconductor device applying a QFN is prepared, for example, by a MAP (molded array packaging) method. With the MAP method, after a plurality of semiconductor chips on a lead frame are sealed in a batch with a sealing resin, cutting apart into individual semiconductor devices, each including a single semiconductor chip, is performed.
The lead frame is constituted, for example, of a metal that contains copper. The lead frame has a lattice-shaped supporting portion. A rectangular die pad and a plurality of leads are formed inside each rectangular region surrounded by the supporting portion. The leads are disposed in a periphery of the die pad. Each lead extends in a direction of facing the die pad. More specifically, each lead has a base end portion connected to the supporting portion and a free end portion formed to an elongate shape extending toward the die pad.
After a semiconductor chip has been die bonded onto each die pad, terminals formed at each semiconductor chip and upper surfaces of leads in the periphery are connected (wire bonded) via bonding wires. When the wire bonding of all of the semiconductor chips is completed, the lead frame is set in a molding die and all of the semiconductor chips on the lead frame are sealed in a batch by a resin. Plating layers arranged to improve solder wettability are then formed on a lower surface of the lead frame and a lower surface of the die pad that are exposed from the sealing resin.
Thereafter, along dicing lines set on the supporting portion, a dicing saw is inserted from a lower surface side of the lead frame and the supporting portion and the sealing resin on the supporting portion are removed. The respective leads are thereby cut off from the supporting portion and the individual semiconductor devices are obtained. With such a semiconductor device, a lower surface of each lead is exposed at a lower surface of the sealing resin and one end surface (cut surface made by the dicing saw) of the lead is exposed from a side surface of the sealing resin.